Hybrid Annual CO2 Emissions

Annual CO₂ Emissions of a Hybrid Vehicle

Hybrid cars pair an internal‑combustion engine with one or more electric motors. A conventional hybrid (HEV) captures braking energy and feeds it back to help the engine, which usually trims emissions 25‑35% vs a pure ICE of similar power. A plug‑in hybrid (PHEV) carries a bigger battery you recharge from a wall outlet, and it can hit up to 50% reduction if the owner charges at home regularly and covers most daily trips on electric power.

The annual estimate runs on kg CO₂/year = (km/year ÷ km per liter) × (g CO₂/liter) ÷ 1000. In Brazil, pump gasoline already has anhydrous ethanol blended in (E27, ~27%), and that drops the per‑liter factor from ~2300 g for pure gasoline down to ~2100 g. Hydrous ethanol (E100) sits near 1500 g/L on a well‑to‑wheel basis once you count the sugarcane lifecycle credits. For certified consumption figures by model, look at the Brazilian CONPET‑INMETRO PBE label and CETESB‑SP dynamometer measurements.

Applications

Use it to weigh HEV against PHEV and ICE in TCO studies, to work out an annual carbon footprint for sustainability reports, to see what switching from gasoline to ethanol blends does, or to check manufacturer claims against the mileage you actually get.

FAQ

Why doesn't a PHEV always halve emissions? That cut only happens if the driver plugs it in every day. Fleet studies (ICCT, 2022) found many PHEVs hardly ever get charged, so they end up acting like heavy HEVs, and at times they do worse than a comparable ICE.

How is ethanol cleaner if it still burns? The sugarcane pulls CO₂ out of the air as it grows, which leaves the net lifecycle balance far below fossil gasoline. In the Brazilian context that works out to roughly 70% less per km.

Should I include charging emissions for the PHEV? Yes, if you want the full accounting. Add (kWh from grid × gCO₂/kWh) on top of the result, and lean on the EV calculator here to handle that part.